USB to 2.1mm DC Booster Cable - 9V (ADA2777)

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This cable is kinda fascinating - it has an integrated boost converter, so you can plug it into any USB port (from a computer, battery pack, etc) and it will give … read more

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Hi there I’m just looking for a usb cord to dc 9v with 2.2 a out put

What is 500ma in amps ?

Hi Leah,

500mA is 0.5 Amps.

There will not be a 9v USB converter that is 2.2A. USBs will have a typical output of 500mA max, and SOMETIMES 1A.

Good Day there,
Just wondering if this cable would work for this:
It has the picture of the inner core negative/ positive. And is requiring 9 volt, 200 to 300 milli-amperes.

Many thanks

Hi All

And don’t forget that is at 5V.
At 9V this 1A will become 0.555A and with 85% conversion efficiency the overall picture is for 1A input at 5V you get 0.472A at 9V. For 500mA (0.5A) halve that to about 236mA.
Cheers Bob

Hi Kassapa

Negative required for your device. (from the diagram)

From the text re that cable “with a center-positive 2.1mm DC barrel jack”. You would have to reverse it.
Cheers Bob

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Many thanks Bob, would this do the trick to reverse the poles?

Also what is the source and output power, I get a little confused at all the numbers, it would provide the 200 , 300, 9v output if the input was?

Many thanks for your help and clear information.

Hi Kassapa
The following assumes 85% conversion efficiency. This apparently gets worse as the current increases.
For 9V @ 200mA out requires 5V @ 423mA in.
For 9V @ 300mA out requires 5V @ 635mA in.

For conversions everything should be converted to Watts (or Watt hours) or Milliwatts (or Milliwatt hours).
If you are unable to do or understand this I would suggest some research into the relationship between Amps, Volts, Resistance and Watts or basic DC theory.

Yes, or you could cut the cable and reverse the connection yourself.
The first thing of course is to establish if the socket on your player device is 2.1mm. These plugs and sockets come in various sizes.
Cheers Bob


Many thanks Bob I shall investigate further,
Peace Kassapa

I once had a case where I waited a very long time for a cable and it didn’t fit the socket size. Since then I measure the socket size first. 2.1mm is the first thing to check.

Many thanks for the information, I shall measure it up